State of the art of high temperature power electronics

Abstract

High temperature power electronics has become possible with the recent availability of silicon carbide devices. This material, as other wide-bandgap semiconductors, can operate at temperatures above 500°C, whereas silicon is limited to 150-200°C. Applications such as transportation or a deep oil and gas wells drilling can benefit. A few converters operating above 200°C have been demonstrated, but work is still ongoing to design and build a power system able to operate in harsh environment (high temperature and deep thermal cycling).

Dielectric properties of BaTiO₃–Bi(Mg_1/2Ti_1/2)O₃ films with preferential crystal orientation

“…No crack or pore structure was observed on the surface of these films. The surface roughness of the films fabricated on (100)SrRuO 3 //(100)SrTiO 3 was relatively smaller than those on (111)Pt/TiO 2 /(100)Si and (111)SrRuO 3 // (111)SrTiO 3 ; the values of root-mean-square roughness (RMS) for these films were 5.4, 9.2 and 9.4 nm, respectively. Roughness of the oriented film is determined by the crystallographic feature: 38),40)42) smooth surface of the film on (100)SrRuO 3 // (100)SrTiO 3 reflects crystalline facet of perovskite (100) plane exposed on the film surface, while the (100) facet can enhance the roughness of (111) oriented films.…”

“…1)4) Conventional high-temperature capacitors consisting of simple oxides such as Al 2 O 3 , MgO, MgTiO 3 and Ta 2 O 5 exhibit significantly stable TCC behavior with «TCC« values below 200 ppm/K. 5)9) However, these materials are still insufficient for the application in integrated electronic devices because of their lower relative dielectric constant (¾ r ) of less than 100.…”

“…5)9) However, these materials are still insufficient for the application in integrated electronic devices because of their lower relative dielectric constant (¾ r ) of less than 100. In contrast, recent high-permittivity capacitors mainly consist of barium titanate [BaTiO 3 (BT)] which exhibit larger ¾ r of above 1000 at room temperature, although it suffers from rapid dielectric variation above the Curie temperature (T c = 120°C) owing to its phase transition from tetragonal to cubic symmetry. 10)12) Therefore BT capacitors hardly utilize for high-temperature application because of its unstable TCC behavior, regardless of high permittivity.…”

Applications, Prospects and Challenges of Silicon Carbide Junction Field Effect Transistor (SIC JFET)

“…Accordingly, the authors in [43] reported application of JFET in converters with operating temperature above 200 0 C. Lateral depletion-mode 4H-SiC n-channel JFETs have been reported to have good performance at temperatures ≤ 600 0 C, which can prove useful in environments such as fuel combustion chambers in vehicles, deep-well drilling, planetary instrumentations, and other harsh environments [44]. This was verified in [45] through demonstration of ICs based on 4H-SiC JFET integrating Hafnium ohmic contact with TaSi 2 interconnect with SiO 2 and SiN 4 dielectric layer hours of stable electrical operation at 500 0 C in the air.…”

Are Sintered Silver Joints Ready for Use as Interconnect Material in Microelectronic Packaging?

“…1,2 This trend coincides with the proliferation of power semiconductor devices, such as silicon carbide and gallium nitride, which require interconnect materials to operate at high switching speeds, high current densities, and junction temperatures of more than 200°C. 3,4 In such a harsh environment, a sintered Ag joint is one of the few viable options because its high melting temperature implies a stable mechanical joint with a low homologous temperature (%0.3 T m ). 5 In addition, the high thermal conductivity of sintered Ag allows devices such as light-emitting diodes and laser diodes to operate at high luminance efficiencies compared with other epoxy-based die-attach materials.…”